Various devices are known that lift and carry workpieces from one station to another. When transferring workpieces into or out of such devices, or from one such device to another, it is usually necessary to precisely synchronize the movement of the devices. Failure to do so usually results in improper transfer of workpieces, failure to transfer workpieces and/or interference or collision of workpieces and/or the devices themselves. Frequently, such devices jar, shock or shift the location of workpieces when they are transferred rapidly.
In some applications, it is also very desirable or even necessary that workpieces be advanced generally horizontally through portions or segments of a processing line at different vertical heights. Frequently, workpieces must be transferred vertically from one height to another because the height to which a workpiece can be manually lifted, due to its weight, is less than the height necessary for performing manufacturing and/or assembly operations. These applications usually present a critical need for and difficult problems in synchronizing the devices moving the workpiece through the transition from one vertical height to another.